we investigated the environmental impact of trout farm discharge on zayandeh-rud river. three farms with different production capacities; 250, 25 and 70 tones were assigned to this study. five sampling sites were designated to each farm. benthic macroinvertebrates were collected in autumn, winter, and spring using the quantitative techniques. a total of 11 classes, 16 orders and 53 families&apo...

This paper presents a synthesis of the main theoretical and empirical contributions that analyse production choices of farm households living and operating in developing countries. The review is particularly concerned with recent micro-economic contributions that highlight the trade-off farm households typically face, between full-income risk and expected return, while making production decisio...

We developed a single-equation decomposed negative binomial regression model (NBRM) of the U.S. farm sector to simultaneously evaluate structural changes in the U.S. agricultural sector and the strength of several economic forces that influenced the changes in farm structure during the 1960–96 period. We found all these forces reinforced economic incentives to increase the size and decrease the...